Azo dyestuffs



Patented Oct. 29, 1935 AZO DYESTUFES Wilhelm Neelmeier, Leverkusen-I. G.Werk, and

August Modersohn,

Cologne-Mulheim,

Ger-

many, assignors to General Aniline Works, Inc, New York, N. Y., acorporation of Delaware No Drawing. Application April 7, 1933, SerialNo. 665,040. In Germany April 25, 1932 4 Claims.

The present invention relates to azodyestufis, more particularly itrelates to dyestuffs which may be represented by the probable generalformula:

x Y Y x l l no N=NQOH Hoot: Y coon wherein one X stands for hydrogen orthe sulfonic acid group and the other X stands for the Sulfonic acidgroup, alkyl or halogen, in such a manner that at least one X representsthe sulfonic acid group, and the Ys stand for hydrogen,

alkyl or halogen.

Our new dyestufis are obtainable by treating with a sulfonating agent anazodyestuif of the general formula:

Y Y X 11000 Y it cool;

wherein X stands for hydrogen, alkyl or halogen and the Ys stand forhydrogen, alkyl or halogen, the manufacture of these dyestuffs beingdescribed for example in German Patent No. 278,613.

Instead of starting with these dyestuffs, one may usethe complexchromium compounds which are described, for example, in French Patent749,- 971 and which are obtainable by heating the 4-amino-1-hydroxybenzene-2-carboxy1ic acid or a nuclear substitutionproduct thereof in the free form or in form of a water-soluble salt witha water-soluble chromium salt containing the chromium'in the trivalentform in water or in an organic solvent and, if desired, with theaddition of a non-diazotiz'able base.

The process is carried out in the usual manner of sulfonating organiccompounds, thereby using for example sulfuric acid monohydrate or fumingsulfuric acid, and due to the working conditions, monoor disulfonicacids are obtained, it being self-understood that on working withstronger sulfonating agents, such as for example a fuming sulfuric acidwith a high SOs-content, and at elevated temperatures, such as forexample at l25-150, generally disulfonic acids being produced, whilemoderately acting sulfonating agents and lower temperatures, such assulfuric acid monohydrate and temperatures from about C. to about C.,generally produce monosulfonic acids.

Our new dyestufis are in form of their alkali metal salts generallyyellowish tobro'wn powders, soluble in water and dyeing wool from .anacid bath, after chroming, generally yellowish to brownish shades ofgood fastness properties.

Example 1..l00 parts by weightof 4.4'-dihy- 5droxyazobenzene-.3.3'edicarboxylic acid are introduced, whilestirring,into 550 parts by weight of sulfuric acid monohydrate, care being takenthat the temperature does not exceed 40 C. Stirring is continuedforabout 5 hoursatroom tempera- 10 ture, thenGO parts by weight ofsulfuric acid containing 65% of 503 are added, and the temperature israised to about to C. and kept at this temperature for about 3 hours.After cooling, the sulfonation mixture is poured onto ice, 15

-the precipitate is filtered, dissolved in water with the aid of soda,and the sodium salt of the dyestuff is salted-out by the addition ofcommon salt. The bulkof the dyestufi is the sodium salt of4.4-dihydroxyazobenzene-3i3'-dicarboxylic acid-5.5-di- 2.0 sulfonic acidhaving in the free state the following formula:

no N: OH 25 l coon 00011 When dried, it is a yellow powder, soluble inconcentrated sulfuric acid with an orange red coloration, dyeing wool,after chroming, clear greenishyellow shades.

When using sulfuric acid monohydrateas sulfonating agent and working ata temperature of about 100 C., the bulk of the dyestuif consists of :the4A+dihydroxyazobenzene-33-dicarbox- 85 ylic acid-5-sulfonic acid of theformula:

C. After cooling, the mass is poured onto ice, dissolved in aqueous sodasolution, and the dyeu stuff having in its free state the followingprobable formula:

SOgH (i711:

SO|H CH l QOOH COOH dyeing, after chroming, somewhat more greenishshades.

By substituting the 5-methyl-1-hydroxybenzene-2-carboxy1ic acid by the5-chloro-1-hydroxybenzene-Z-carboxylic acid, there is obtained adyestufi of the following probable formula:

00H coon dyeing, after chroming, somewhat more reddish shades.

Example 3.-50 parts by weight of the chromium complex compound of thedyestuff from d-amino-1-hydroxybenzene-2-carboxylic acid and salicylicacid are introduced, while stirring, into 175 parts by weight ofsulfuric acid monohydrate. After heating for 3 hours at a temperature ofto C., the mass is poured onto ice, after cooling. The precipitate isfiltered, washed with a solution of common salt, until free fromchromium, then it is dissolved in aqueous soda solution, and the sodiumsalt of the dyestuff is salted out by the addition of common salt.Thedyestufi is a mixture of 4.4-dihydroxyazobenzene-3.3-dicarboxylicacid-5-monoand -5.5-disulfonic acid, the bulk being disulfonic acid.

The starting dyestufi is obtainable according tion into an aqueouscaustic soda alkaline solution prepared in the usual manner from thecalculated quantity of salicylic acid, care being taken that during thecoupling ice is present and that the solution reacts caustic alkaline. 5

We claim:

1. Azodyestufis of the general formula:

x "5|! Y X H000 Y Y COOH wherein one X stands for hydrogen or thesulfonic acid group and the other X stands for the sulfonic acid group,alkyl or halogen, in such 15 a manner that at least one X represents thesul- 30011 OOH wherein X stands for hydrogen, the sulfonic acid group,alkyl or halogen, being in the form of their alkali metal saltsgenerally yellowish to brownish powders, soluble in water, and dyeingwool from an acid bath, after chroming, generally yellowish to brownishshades of good fastness properties.

3. The azodyestufi. of the following formula:

SOaH' SOaH V OOH (300K being in form of its alkali metal salts a yellow5 powder, soluble in concentrated sulfuric acid with an orange redcoloration, and dyeing wool, after chroming, clear greenish-yellowshades of good fastness properties.

4. The azodyestufi of the following formula:

SOIH

being in form of its alkali metal salts a yellow powder, soluble inconcentrated sulfuric acid with an orange red coloration, and dyeingwool, after chroming, clear greenish-yellow shades .of 00 good fastnessproperties.

WILI-IELM NEELMEJER. AUGUST MODERSOHIN.

